What is the Affordable Warmth Obligation? ECO4 explained
ECO4 is a government energy-efficiency scheme that requires medium and large energy suppliers to support upgrades for low-income and vulnerable households.
What is the Affordable Warmth Obligation?
The Affordable Warmth Obligation is an older name for the Home Heating Cost Reduction Obligation (HHCRO) — the legal duty on medium and large energy suppliers to fund energy-saving upgrades for low-income and vulnerable households. Today that obligation is delivered through ECO4, the fourth and final phase of the government's Energy Company Obligation scheme.[1]
The scheme is designed to help households that struggle with high energy bills by improving how well their homes hold heat. It is a £4 billion programme, and support can cover some or all of the cost of the work. ECO is not a grant scheme: your energy supplier and installer decide the level of funding for each project, so you may be asked to contribute towards the installation.[2]
The value of the upgrades installed varies from home to home, depending on your property's condition and the package of measures needed — funding is agreed project by project. The scheme is regulated by Ofgem on behalf of the Department for Energy Security and Net Zero. However, time is running out to apply. Funding is becoming limited, and the scheme will shut completely at the end of 2026.
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What upgrades does the scheme cover?
In the past, energy grants often paid for a single quick fix, such as swapping an old gas boiler for a new one. The current ECO4 scheme works differently. It uses a whole-house retrofit approach. This means the scheme looks at your entire home and installs a package of measures designed to work together.
The main goal is to improve your home's Energy Performance Certificate (EPC) rating. The upgrades will normally aim to meet the relevant minimum EPC improvement target: band C for homes starting at band D or E, and band D for homes starting at band F or G. Because of this rule, you cannot pick and choose which upgrades you want. A qualified retrofit assessor will survey your home and decide exactly what work is needed to hit the target.[1]
Typical measures installed
- Insulation: This is usually the first step. It includes solid wall, cavity wall, and loft insulation to stop heat escaping.
- Air source heat pumps: The scheme heavily focuses on moving homes away from fossil fuels and towards renewable heating.
- Solar panels (PV): These may be installed to help power a new heat pump or reduce your electricity bills.
Because the scheme takes a whole-house approach, the work can cause a lot of disruption. You might need to clear your loft for insulation, or move furniture away from external walls so solid wall insulation can be fitted. It is not a fast process, but the long-term savings on your energy bills can be substantial.
Who is eligible for the Affordable Warmth Obligation?
To get help through the scheme, your home must meet the relevant energy-efficiency rules. You may qualify through government benefits, as a social-housing resident in an eligible low-EPC home, or through ECO4 Flex.
Qualifying through benefits
The most common way to qualify is by receiving a means-tested benefit. When ECO4 launched, the government removed the complex income thresholds and extra rules that used to apply to these benefits. Now, if you receive one of the following, you automatically meet the personal eligibility criteria:
- Universal Credit
- Pension Guarantee Credit
- Pension Credit Savings Credit
- Housing Benefit
- Income Support
- Income-related Employment and Support Allowance (ESA)
- Income-based Jobseeker’s Allowance (JSA)
Child Benefit can also qualify you for the scheme, but it is the only benefit that still has an income cap applied. The income limit depends on whether you are a single parent or part of a couple, and how many children you have.
Qualifying without benefits (LA Flex)
If you do not receive any of the benefits listed above, you might still get help through the Local Authority Flexibility route, known as LA Flex. Energy suppliers can use this route to meet up to 50% of their legal obligation.
Under LA Flex, your local council can refer you to the scheme if your gross household income is below £31,000 a year. They can also refer you if someone in your household has a severe or long-term health condition that is made worse by living in a cold home, such as a respiratory or cardiovascular disease.
Property and EPC requirements
Even if you meet the personal income or benefit rules, your home must also qualify. ECO4 targets the least efficient homes in the country, so properties that are already well-insulated will not be accepted.
Eligibility is based on your home's current EPC rating. If you do not know your rating, you can check it on the government's EPC register online.
| Housing type | Eligible EPC ratings | Conditions |
|---|---|---|
| Private housing (owned or rented) | Owner-occupied: D, E, F or G. Private rented: E, F or G. | Private tenants must have their landlord's permission before any work can begin. |
| Social housing | E, F, or G | Measures are limited to insulation, first-time central heating, renewable heating, district-heating connections and innovation measures. |
| Social housing | D | Limited to innovation measures and insulation needed to meet the minimum insulation requirements. |
In the past, some energy grants used council tax bands to decide who could apply. This was mainly a feature of the Great British Insulation Scheme (GBIS). However, GBIS officially closed to new applications on 31 March 2026. As a result, council tax bands are no longer a primary way to check if you qualify for the remaining ECO4 funding.
How the process works and how long it takes
Getting a whole-house retrofit is a major project. It is not as simple as calling an energy supplier and booking a date for a quick installation. There is no fixed timescale — how long it takes depends on your installer, the survey findings and the measures being fitted.
The end of ECO4 and the new Warm Homes Plan
ECO4 is now in its final months. The scheme was originally supposed to end on 31 March 2026, but the government granted a nine-month extension to support remediation work and an orderly, controlled closure. The hard deadline for the scheme is now 31 December 2026.[1]
The Chancellor confirmed in the Autumn 2025 Budget that the Energy Company Obligation framework is being scrapped entirely. There will be no ECO5. Instead, support will move to a new system.
If your home needs urgent upgrades, do not wait to see what the Warm Homes Plan will offer you — it was published in March 2026 and its schemes will roll out over the coming years. Apply for the current scheme now while the funding is still available.[2]
How to apply
You do not have to be a customer of a specific energy supplier to get help from them. Any medium or large supplier taking part in the scheme can fund upgrades in your home, even if you buy your gas and electricity from someone else. Suppliers involved include British Gas, EDF Energy, E.On Next, ScottishPower, and Octopus Energy.
To start an application, you can go directly to a participating energy supplier's website and look for their ECO4 or home insulation pages. They usually have a short online form to check your eligibility.
Alternatively, you can contact your local council. This is especially useful if you do not receive benefits but earn under £31,000, as the council will need to process you through the LA Flex route. Many councils partner with approved local installation companies who handle the paperwork and the building work on their behalf.
Frequently asked questions
Can I just get a free replacement gas boiler?
Not usually. ECO4 is not designed as a boiler-replacement scheme: it normally uses a whole-house approach, with insulation often needed before heating measures. Separate annual caps apply to certain repairs and replacements: up to 5,000 repairs a year of efficient boilers and electric storage heaters, plus oil, LPG and biofuel boilers; and up to 5,000 homes a year where a broken efficient system cannot be economically repaired and is replaced like-for-like. Replacing an old, inefficient boiler is not capped, so check with an obligated supplier rather than ruling yourself out.
Sources
Do I have to be on state benefits to get help?
Not necessarily. While receiving a means-tested benefit is the most common way to qualify, you can also apply through the LA Flex route. This allows local councils to refer households with an income under £31,000, or those with health conditions made worse by the cold.
Will I have to pay anything towards the upgrades?
Not always. Suppliers and installers decide the level of ECO4 funding for each project, so support may cover all or only part of the cost and a customer contribution can sometimes be requested.
Sources
Can I choose which upgrades are installed?
Not usually. ECO4 uses a whole-house assessment and has different minimum targets: band C for homes starting at D or E, and band D for homes starting at F or G. A certified retrofit assessor will survey your property and decide exactly which combination of measures is needed to reach that target.
Sources
When does the Affordable Warmth Obligation end?
ECO4 installations must be completed by 31 December 2026. Suppliers may stop accepting new applications earlier, so contact an obligated supplier promptly to check whether funding remains available.
Sources
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Written by
Rob Gibbs
Hi, I'm Rob, and I run Energy-Review.co.uk. I initially started this project in 2018 when I was looking to switch energy suppliers and found there wasn't a website that provided simple, data-backed reviews on all the suppliers available. Since then, I have spent a lot of time (too much, some may say!) looking at all publicly available data about each supplier and writing reviews using this information. These reviews are updated as regularly as possible, and any data is backed up by a source where necessary. I have also started writing guides on various energy-related topics, which hopefully you will find useful. If you find any issues, please use our contact form to let us know.